The invention relates to a parallel spinning process and to spinning machines equipped therewith, in particular for filaments, e.g. for textile or industrial applications, made from polymers such as polyester or polyamide, in each case having a thread interlacing device between two godets.
Spinning machines for conventional POY (partially oriented yarn) spinning processes are usually equipped with two separately driven, speed-regulated godets over which a plurality of threads (four, six or eight, depending on the winder) are guided in an S-shaped threadline in order to regulate the thread tension between the thread lubrication point and the take-up device. In this threadline, the freshly spun sheets of filaments are first guided in a parallel manner next to one another to the corresponding thread lubricating devices and are each combined there to give a cohesive thread, and then the threads are guided, grouped closely next to one another, over the aforesaid godets. The thread sheet is then fed to the winder, opened out again and turned through 90° to correspond to the desired bobbin width. In order to achieve better cohesion of the thread, pneumatically operated devices for tangling the threads, so-called tangle jets or interlacers, are frequently used. This is advantageously carried out between the godets: on the one hand, the thread tension can still be regulated, and on the other hand it is easier to insert the thread through the narrow thread gap.
In contrast to this crossed threadline (the extrusion axis is turned through 90° with respect to the winder axis), no simple solution or in fact no solution at all has been found for the arrangement of interlacers and handling between the godets in the parallel spinning process, such as in U.S. Pat. No. 3,902,853.
More modern parallel spinning processes have hitherto mainly been designed as SHSS (super-high-speed spinning, Lurgi Zimmer) or HOY (high oriented yarn) processes, in which the line runs directly, i.e. without godets, to regulate the thread tension, in a parallel and perpendicular manner out of the spinnerets to the winder. This low-cost, compact design is not entirely advantageous, however: as well as the process engineering disadvantages regarding the uniformity of the threads, the bobbin building and the limited range of titres, the threading in and feeding at the start of the spinning process in these space-saving types of short spinning machines is very time-consuming and highly inconvenient.
For POY spinning processes, parallel spinning machines have hitherto usually been equipped with two very expensive long godets, such as, for example, according to WO 96/09425, between which the tangle jets are accommodated. Here too, the threading-in and feeding is tedious and inconvenient, and moreover the feeding requires a certain amount of space simply for reasons of safety.
A further POY spinning process in which a small pair of godets is provided for each thread was presented in Paris by Barmag at the ITMA in June 1999. In this design, interlacers cannot be accommodated between the small godets. Although this solution is substantially less expensive than the long godet version, the fact that the function of regulating the thread tension is insufficiently fulfilled in this arrangement with small godets, given the small angle of wrap of less than 90°, means, however, that separate drives and speed regulation are logically omitted. Thus, there are considerable process-related disadvantages to counter the low investment costs: an inadequate angle of wrap, no regulation of the speed or thread tension, a lack of entangling between the godets and a considerable space requirement when setting up the machine for the time-consuming threading-in and feeding.
Thus, for POY spinning processes in parallel spinning machines, the object is to find a device for regulating the thread tension and for thread interlacing which is easy to operate and has better performance.
According to the invention, this object is achieved by the process and the device according to the claims.
In the arrangement of godets and interlacers according to the invention, the object is achieved at the same time as surprisingly operator-friendly handling and complete fulfillment of the desired functions. The new concept provides major process and handling advantages which mean that the higher investment quickly pays for itself over the operating time: a very large angle of wrap of more than 180° is achievable, as is thread interlacing between the godets and the use of speed-regulated drives to control the thread tension. Furthermore, the automatic threading into the tangle jets and over the godets, which is a surprising solution for handling, improves the effectiveness of the machines as a result of shorter feeding times.